The controversial U.S. military air base on Japan’s southern prefecture of Okinawa will be relocated to another part of the island after a decision by prefecture governor Hirokazu Nakaima.

The ruling follows 17 years of protests stemming from safety and environmental concerns, and is sure to be unpopular with many on the island. Nakaima was elected largely on the back of his campaign promise to permanently close the military installation.

Despite local opposition, Tokyo is keen to maintain Japan’s long-standing relationship with the U.S. as a counterweight to territorial disputes with China. Around 26,000 American troops are currently stationed in Okinawa as part of a security alliance.